Practice Exam for Divemaster Physics – Created by Heidi Wilken – Oceans Keeper Scba – !ersion "#$
Divemaster Physics – Exam Version H "# %n ob&ect 'ei(hs )*+lbs and and displaces , cbic feet of 'ater# 'ater# Disre(ardin( the minimal minimal displacement displacement of the lead- ho' mch lead 'ei(ht do yo need to make it $$ lbs ne(atively boyant in sea 'ater. /0ond to the closest lb#1 $# %n ob&ect 'ei(hs 'ei(hs ,23lbs and displaces displaces )#$ cbic feet feet of 'ater# 'ater# Ho' mch additional additional sea 'ater 'ater do yo need to displace to (ive the ob&ect 43 lbs positive boyancy. /0ond to the closest cf#1 )# 5o take a (as volme of 6 litres litres in a flexible container from from the srface to a depth of 23 ft in sea 'ater# 'ater# What 'ill the ne' volme be- and 'hat 'ill the density be compared to the srface. /0ond to the one decimal place#1 !olme 7 88888888888888 Density 7 888888888888888 888888888888888 6# 5o take 6#* litres9cbic litres9cbic feet of (as in a flexible container container from ""+ feet in fresh fresh 'ater to 3" feet# What 'ill the the ne' volme be. /0ond to one decimal place#1 *# % diver consmes "62psi per minte minte at """ feet in sea 'ater 'ith 'ith a (iven cylinder# :sin( the the same cylinder- 'hat is is the diver;s consmption rate at 24 feet. / oxy(en- ,2> nitro(en# nitro(en# What 'ill 'ill the partial partial pressres of oxy(en oxy(en and nitro(en be at a depth of ,) ft in sea sea 'ater. /0ond ata to t'o decimal decimal places# 1 PO$ 7 88888888 88888888 P=$ 7 8888888888888888888888 3# When breathin( air air at 6, feet in sea 'ater- the the physiolo(ical effect effect of oxy(en is the same as breathin( breathin( approximately approximately 'hat percent oxy(en at the srface# 4# 5o plan to recover an anchor in sea 'ater 'ater that 'ei(hs ,*+ lbs# ?t ?t displaces 6#", cbic feet of 'ater# 'ater# Ho' many cbic feet of air do yo need to add to a liftin( device to make the anchor netrally boyant. /0ond to the closest 'hole cbic foot1# "+#%n "+# %n ob&ect displaces 4#, cf of fresh 'ater- 'hich (ives the ob&ect *44 lbs positive boyancy in fresh 'ater# ?f the ob&ect is placed in sea 'ater- ho' mch lead 'ei(ht 'ill need to be added to the ob&ect to make it netrally boyant. /0ond to the closest 'hole lb#1 ""#5o ""# 5o take a (as volme of )#3 litres in a flexible container from the srface to a depth of 3+ ft in fresh 'ater# What 'ill the volme be. What 'ill be the density be compared to the srface. /0ond to one decimal place1 "$#5o "$# 5o take *#4 litres of (as in a flexible container from ") feet in sea 'ater to 2* feet# What 'ill the ne' volme be. /0ond to one decimal place#1 ")#% ")# % diver consmes )+ psi per minte at )) feet in sea 'ater 'ith a (iven cylinder# :sin( the same cylinder- 'hat is the diver;s consmption rate at 4$ feet. /0ond to the closest 'hole psi1 "6#What "6# What is the partial pressre of oxy(en in air at ")$ft in sea 'ater. /0ond ata to t'o decimal places1 "*#% "*# % diver sin( enriched air that consists of 6+> oxy(en- ,+> nitro(en# What 'ill be the partial pressres of oxy(en and nitro(en at a depth of *4 ft in sea 'ater. /0ond ata to t'o decimal places1 ",#?f ",# ?f a (as mixtre has *> carbon dioxide- breathin( it at 23 feet in sea 'ater 'old be e@ivalent of breathin( 'hat percenta(e of carbon carbon dioxide at the the srface. /0ond to one decimal place1
Practice Exam for Divemaster Physics – Created by Heidi Wilken – Oceans Keeper Scba – !ersion "#$
Answer Key – Divemaster Physics Exam Version H "# *, lbs# Do'n'ards force 7 )*+ lbs# :p'ards force 7 , c ft displaced A ,6 7 )36 lbs# =et force to netral 7 )6 lbs p /)36 p – )*+ do'n1# Bherefore 'ei(ht needed is )6 $$ 7 *, lbs to achieve $$ lbs ne(ative boyancy# $# 4 c ft /3#4$* 'ithot rondin(1# Do'n'ards force 7 ,23 lbs# :p'ards force 7 )#$ c ft A ,6 7 $+6#3 lbs# =et force to netral 7 62)#$ lbs do'n /,23 do'n – $+6# 3 p1# Bherefore air needed to is 7 *2"#$ lbs /62)#$ 431 > ,6 7 3#4$* c ft of air# )# !olme 7 "#"4 c ft# Density 7 )#), time# )#), /23 ft 9 ))ft " for air 7 )#), atm absolte1# )#6* 7 *#*" c ft volme# Bhis makes sense becase 'e bro(ht it to a shallo'er depth- so 'e expect the volme to be bi((er# *# ""6 psi9min# """ ft /6#), atm absolte pressre – )#), for 'ater- " for air1 air consmption is "62 psi9min# Bake p to the srface by dividin( by pressre# "62 psi9min > 6#6, atm 7 ))#2" psi9min at + ft# 5o can remember to divide by realiin( yo shold end p 'ith a smaller nmber becase yo se air less @ickly at the srface# Bhen take do'n to ne' depth# ))#2"psi9min A /24ft 9 )) ft " atmosphere for air 7 )#)4)41 7 ""6 psi9min# ,# #36 ata# Fltiply nmber of atmospheres /44 > )) 7 ) " for air 7 6 total ata# 1 A percenta(e of Oxy(en in air# Standard air is $" > Oxy(en- 23 > =itro(en# $" > /or #$"1 A 6 7 #36 2# Oxy(en pp #4, 7 =itro(en pp 7 "#46# Calclate atmospheres absolte# ,) ft 9 )) ft 7 "#4+ ambient atm " for air 7 $#4 ata# $#4+ata A )) > /or #))1 7 #4*2pp Oxy(en# $#4 ata A ,2 > /or #,21 7 "#46) pp# 3# *+># 6, ft9))ft 7 "#)4 atmospheres ambient " for air 7 $#)4 absolte# $#)4atm A $" > oxy(en 7 #* partial pressre'hich is the same as breathin( air that is *+ > oxy(en at the srface /aka " atmosphere absolte1 4# , c ft# Do'n'ards force 7 ,*+# :p'ards force 7 6#", c ft A ,6 lbs 7 $,,#$6 lbs# =et force 7 ,*+ do'n – $,,#$6 p 7 )3)#2,# %ir needed 7 )3)#2, > ,6 7 *#44 c ft or , c ft# "+#,"6 lbs# 4#, c ft A ,6 lbs for salt 'ater – ,"6#6 lbs positive boyancy# Bo make netral- add this same amont# ""#!olmeG "#" c ft DensityG )#6$ /3+ ft 9)) ft " for air1 7 "#"+4 c ft# Density is simply pressre at ne' depth so )#6$# "$#$#* c ft# *#4 c ft A /") ft 9 ))ft " for air 1 7 3#$$ c ft at + ft# 3#$$ > /2* ft9)) ft " for air1 7 $#* c ft# ")#*2 psi9min# )) ft /$ atm absolte pressre – " for 'ater- " for air1 air consmption is )+ psi9min# Bake p to the srface by dividin( by pressre /$ atm1 )+ psi9min > $ 7 "* psi9min at + ft# 5o can remember to divide by realiin( yo shold end p 'ith a smaller nmber becase yo se air less @ickly at the srface# Bhen take do'n to ne' depth# "*psi9min A /4$ft 9 )) ft " atmosphere for air 7 )#23231 7 *,#3" psi9min# "6#"#+*pp# Fltiply nmber of atmospheres / ")$ > )) 7 6 " for air 7 * total ata# 1 A percenta(e of oxy(en in air# Standard air is $" > Oxy(en- 23 > =itro(en# $" > /or #$" 1 A * 7 "#+* "*#Oxy(en pp 7 "#""# =itro(en pp 7 "#,2# *4 ft9 ))ft 7 "#23 ambient pressre " for air 7 $#23 absolte# $#23ata A 6+> O$ /or #6+1 7 "#""pp O$# $#23ata A ,+> =itro(en /or #,+1 7 "#,2 pp =$# ",#"2>#23ft9))ft 7 $#), ambient pressre " for air 7 )#), absolte# )#),ata A *> /or #+*1 7 #",3pp or "2>
